JPH07287130A - Optical fiber module - Google Patents

Abstract

PURPOSE:To provide an optical fiber module having a structure capable of efficiently exhibiting the cooling capacity of an electronic cooling element and efficiently cooling an optically active element. CONSTITUTION:This optical fiber module is formed by housing the optically active element 1 and the electronic cooler 31 into a package 32 and is constituted to optically couple the internal optically active element 1 and an external optical fiber 12. The module described above is so formed that the heat radiation plate 312 of the electronic cooler 31 is utilized as part of the outside walls of the package 32. Thermal resistance is lowered and the direct heat radiation of the heat generated by the optical active element 1 is made possible by using the heat radiation plate 312 of the electronic cooler 31 as part of the outside walls of the package 32.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of an optical fiber module used for optical fiber communication and accommodating optically active elements such as a light emitting element and a light receiving element and optically coupling with an optical fiber.

[0002]

2. Description of the Related Art Conventionally, in optical fiber communication,
A single mode laser diode is used for long distance communication, and a high light output laser diode is used for an optical amplifier applied to a relay system, optical image distribution, and the like. In order to maintain the stability of the optical output of the LD and the stability of the optical spectrum, an optical fiber module that optically couples a light emitting element (hereinafter collectively referred to as LD) represented by these semiconductor lasers with a transmission optical fiber is used. In addition to packaging and hermetically sealing, a thermoelectric cooler is built in to keep the internal temperature constant. Hereinafter, a typical structure of the conventional optical fiber module will be briefly described by showing about three examples.

FIG. 4 shows a first conventional optical fiber module.
3 is a cross-sectional view showing a structural example of FIG. In FIG. 4, 1 is L
D, 2 are heat sinks that radiate the heat generated by LD1, 3 are L
This is an LD header in which D1 and the heat sink 2 are bonded. Reference numeral 4 is a support plate to which an LD header is attached.
Since the LD header 3 and the support plate 4 have good heat dissipation,
It is fixed by a method such as soldering. Reference numeral 5 denotes a temperature detecting thermistor resistance (hereinafter, simply referred to as a thermistor) for measuring the temperature of the LD 1, which is fixed to the support plate 4 by adhesion or soldering.

Reference numeral 7 is a lens for focusing and converting the output light of the LD 1, and reference numeral 8 is a lens holder 8 for holding the lens 7 from the support plate 4 at the same height and in the same direction as the optical axis of the LD 1. The lens 7 is attached to the lens holder 8 by soldering, press fitting, etc., and the lens holder 8 is mounted on the support plate 4 in the YA form.
It is welded and fixed with a G laser or the like.

Reference numeral 16 denotes a package for housing and protecting the LD portion having the above-described structure, which has a casing structure with one side surface opened, and a window 161 is formed so that the output light of the LD 1 passes. An electronic cooler 15 is attached to the inner bottom surface by soldering, and the LD section is placed on the cooling surface of the electronic cooler 15 and fixed by soldering.

The electronic cooler 15 is formed by connecting the heat absorbing plate 151 and the heat radiating plate 152 by the electronic cooling element 153. When the driving power is supplied to the heat absorbing plate 151 and the heat radiating plate 152, the heat absorbing plate 151 is connected to the LD section. Absorbs heat generated by
The absorbed heat is released to the outside of the package 16 from the heat dissipation plate 152. That is, by driving and controlling the electronic cooler 15 based on the temperature information detected by the thermistor 5, the temperature of the LD section can be kept constant.

A cover 9 hermetically seals the LD portion by closing the opening surface of the package 16 is fixed to the package 16 by seam welding after enclosing nitrogen gas. 1
Reference numeral 0 denotes an optical isolator, which is held in the optical isolator holder 11 by adhesion or welding, and functions so that the beam, which has been focused and converted by the lens 7, does not become return light after passing through the beam, and has the same optical axis as the lens 7. It is fixed by welding on top.

Reference numeral 12 is an optical fiber for inputting and transmitting the output light of the LD 1 through the lens 7 and the optical isolator 10.
Reference numeral 13 is a ferrule for fixing the optical fiber 12. 1
Reference numeral 4 denotes a metal sleeve for integrally holding the ferrule 13 with respect to the package 16. After adjusting the optical axis position, the metal sleeve 4 is welded and fixed by a YAG laser or the like.

Although not shown, the LD header 3, the thermistor 5, and the electronic cooler 15 are wired by wire bonding or the like to the Au metallized pattern on the ceramic or the metal lead protruding into the package 16.

FIG. 5 shows a second conventional optical fiber module.
3 is a cross-sectional view showing a structural example of FIG. In addition, in FIG.
The same parts as the above are indicated by the same reference numerals, and the description thereof will be omitted.

In FIG. 5, reference numeral 17 is an L-shaped support plate 17 to which the LD header 3 to which the LD 1 and the heat sink 2 are bonded and the thermistor 5 are attached. The LD header 3 and the support plate 17 are fixed by soldering or the like in order to improve heat dissipation. The thermistor 5 and the support plate 17 are fixed by adhesion or soldering. L-shaped support plate 17
Is mounted on the cooling surface of the electronic cooler 15 and fixed by soldering. Further, a window 171 is formed in the upright plate portion so that the output light of the LD 1 passes through.

Reference numeral 18 denotes a metal optical system holder which holds the lens 7 and the optical isolator 10 so that their optical axes coincide with each other. The lens 7 is fixed to the holder 18 by soldering, press fitting, or the like, and the optical isolator 10 is bonded or the like.
The optical system holder 18 is inserted through the opening window 162 formed in the package 16 and adjusted in optical axis with the LD 1.
The upright plate portion of the L-shaped support plate 17 is welded and fixed with a YAG laser or the like.

Further, a metal sleeve 1 having an optical fiber 13 fixed to an optical system holder 18 via a ferrule 13.
4 is welded and fixed after the optical axis adjustment. Further, the optical system holder 18 is soldered to the opening window 162 of the package 16,
It is fixed by adhesion.

FIG. 6 shows a third conventional optical fiber module.
3 is a cross-sectional view showing a structural example of FIG. In addition, in FIG.
The same parts as the above are indicated by the same reference numerals, and the description thereof will be omitted.

In FIG. 6, 19 is a heat sink that radiates heat from the LD 1, 20 is an LD header to which the LD 1 and the heat sink 19 are bonded, and the heat sink 19 and LD
The header 20 is fixed by soldering or the like in a direction perpendicular to the optical axis direction of the LD 1. The LD header 20 is the electronic cooler 15.
It is fixed by soldering etc. in an upright state.

Reference numeral 21 is a cylindrical cap that hermetically seals the LD 1 and is a glass window 21 through which light from the LD 1 passes.
1 is formed. This cap 21 is the LD header 2
It is fixed by 0 and resistance welding.

The optical system holder 18 holding the lens 7 and the optical isolator 10 is adjusted in the optical axis with the LD 1 as in FIG. 5, and then fixed by welding with the cap 21 and a YAG laser or the like. In addition, the metal lead protruding from the LD header 20 is
Although not shown, it is wired by soldering or the like to the Au metallized pattern on the ceramic or the metal lead protruding inside the package 16.

That is, the conventional optical fiber module for optically coupling the light emitting element and the transmission optical fiber is basically configured as described above, and the light emitted from the LD 1 is condensed by the lens 7 to generate the light. The isolator 10 suppresses the returning light and makes it incident on the optical fiber 12.

By the way, in order to keep the temperature of the optical fiber module as described above constant, it is generated by attaching the package 16 to a heat sink 22 such as aluminum as shown in FIG. A heat pump system in which the heat flow is cooled by the electronic cooler 15 and radiated to a heat sink is adopted.

However, in the conventional optical fiber module having the above-mentioned structure, since the bottom surface of the package 16 is interposed between the electronic cooler 15 and the heat sink 22, the thermal resistance is large and the heat dissipation is poor. If an attempt is made to increase the applied power applied to the electronic cooler 15 by that amount, self-heating increases, so the applied power must be increased synergistically. As described above, conventionally, the cooling capacity of the electronic cooler 15 has not been fully utilized.

Further, in the structure shown in FIGS. 5 and 6, since the optical system holder 18 and the opening window 162 of the package 16 are fixed by soldering, adhesion or the like, the hermetic sealing tends to be insufficient, and the LD 1 Oxidation and corrosion occur in the soldered part of
There is a possibility that the characteristic of D1 may be deteriorated or the optical axis may be displaced.

Particularly, in the structure shown in FIG. 6, the LD header 1
9 has a small contact area between the electronic cooler 15 and LD1.
The ability to cool the heat generated from is not fully utilized.

Although the optical fiber module for optically coupling the light emitting element and the optical fiber has been described above, the same problem occurs in the module for optically coupling the light receiving element and the optical fiber.

[0024]

As described above, in the conventional optical fiber module in which the optical active element is built in the package and optically coupled with the optical fiber, the cooling of the electronic cooling element for maintaining the temperature of the optical active element is performed. There was a problem that the cooling efficiency was poor because the capacity was not fully utilized. In addition, the type in which the optical system holder is inserted into the package structurally leaks airtightly, and the mounting part of the optical active element is oxidized and corroded, which deteriorates the optical input / output characteristics and the optical axis shift. There was a problem that it might occur.

Therefore, the present invention has been made to solve the above problems, and provides an optical fiber module having a structure capable of efficiently exhibiting the cooling capacity of an electronic cooling element and efficiently cooling an optically active element. Is the first purpose.

A second object of the present invention is to provide an optical fiber module which is a type in which an optical system holder is inserted into a package and which can hermetically seal an optically active element.

The ultimate purpose is to provide an optical fiber module that can obtain a stable optical output even in the long term.

[0028]

In order to achieve the first object, the present invention accommodates an optical active element and an electronic cooling element in a package, and installs an optical active element inside and an optical fiber outside the optical fiber. The first feature of the optical fiber module to be coupled is that the heat dissipation plate of the electronic cooler is used as a part of the outer wall of the package.

Further, in order to achieve the above second object, the present invention accommodates an optical active element and an electronic cooling element in a package, and an optical system holder is inserted into the package, and the optical active element inside and the external In an optical fiber module that optically couples the optical fiber with the optical fiber via an optical system held by an optical system holder, the optical active element is hermetically sealed in a small housing having a light transmitting window on the optical axis plane. This is the second feature.

Further, a third feature of the present invention is that the structures having the above first and second features are combined.

[0031]

In the optical fiber module having the first characteristic structure, the heat dissipation plate of the electronic cooler is formed as a part of the outer wall of the package, so that the heat resistance can be reduced and the heat generated by the photoactive element can be directly radiated. I am trying.

In the optical fiber module having the second characteristic structure, the optical active element is hermetically sealed inside the package by a small case, whereby the junction between the package and the optical system holder is hermetically sealed. Even if a leak occurs, it does not affect the photoactive device.

[0033]

Embodiments of the present invention will be described in detail below with reference to FIGS.

FIG. 1 is a sectional view showing the structure of the first embodiment of the optical fiber module according to the present invention. In FIG. 1, the same parts as those in FIG. 4 are designated by the same reference numerals, and different parts will be mainly described here.

In FIG. 1, reference numeral 31 denotes an electronic cooler on which an LD section is mounted, which is composed of a heat absorbing plate 311, a heat radiating plate 312, and an electronic cooling element 313. Heat absorbing plate 311 and heat radiating plate 312
Is made of ceramics, etc.
It is formed sufficiently larger than 1 and is used as an outer wall of the bottom surface of the package 32. The LD unit is mounted and fixed on the heat absorbing plate 311.

The package 32 is made of a metal such as Cu-W or KOVAR, has an open bottom surface, and the heat radiating plate 312 of the electronic cooler 31 is fixed to the bottom surface side by gluing. A cover 9 is fixed to the upper surface side by seam welding after enclosing nitrogen gas. The package 32
A window 321 is formed in a portion through which the output light of the LD 1 passes, and the optical isolator holder 11 is fixed to the portion after the optical axis adjustment.

According to the optical fiber module having the above structure, the bottom surface of the package 32 for protecting the LD 1, the heat sink 2, the LD header 3, the support plate 4, the thermistor 5, the lens 7, and the lens holder 8 and the heat dissipation plate of the electronic cooler 31. 31
Since 2 is fixed by gluing and both are integrated, there is almost no thermal resistance when attached to an external heat sink,
As a result, heat dissipation is improved, and the drive efficiency of the electronic cooler 31 can be improved.

In addition, since the bottom surface of the package 32 and the heat dissipation plate 312 of the electronic cooler 31 are shared, the height of the optical fiber module is reduced by about one board, which facilitates mounting on the transmission device. There is also.

In the above embodiment, as shown in FIG. 2A, the outer wall of the package 32 having the window 321 through which the output light of the LD 1 passes and the heat radiating plate 312 of the electronic cooler 31 are formed.
2 is made vertical, but in the case of the structure shown in FIG. 6, as shown in FIG. 2B, the outer wall of the package 32 on which the window 321 is formed and the electronic cooler 31.
If the heat radiating plates 312 are formed and fixed so that they are parallel to each other, the same effect as in the above embodiment can be obtained.

FIG. 3 is a sectional view showing the structure of the second embodiment of the optical fiber module according to the present invention. 3, the same parts as those in FIG. 5 are designated by the same reference numerals, and different parts will be mainly described here.

In FIG. 3, reference numeral 33 denotes a small housing having an open top surface and a U-shaped cross section. The housing 33 is fixed on the heat absorbing plate 151 of the electronic cooler 15, and has an LD1 and a heat sink 2 on the inner bottom surface. The LD header 3 and the thermistor 5 bonded to are fixed. After filling with nitrogen gas, the cover 34 is fixed to the top surface by seam welding. L of case 33
A window 331 is formed in the output light passage portion of D1.

Then, as in FIG. 5, the window 33 of the casing 33 is formed.
The optical system holder 18 to which the lens 7 and the optical isolator 10 are attached is welded and fixed to the formed portion 1 by a YAG laser or the like after adjusting the optical axis. The optical system holder 18 is fixed to the end portion of the opening window 162 of the package 16 by soldering, bonding or the like.

According to the optical fiber module having the above structure, since the LD 1 is sealed inside the package 16 in the box-shaped container by the housing 33 and the cover 34, the LD portion can be kept airtight. , LD1 is prevented from being deteriorated, and stable optical output can be obtained for a long period of time.

Further, if the contact area between the housing 33 to which the LD 1 is attached and the electronic cooler 15 is increased, the heat absorption is further improved, and the driving efficiency of the electronic cooler 15 can be improved. .

FIG. 8 is a sectional view showing the structure of the third embodiment according to the present invention. This embodiment is an optical fiber module having a structure in which the electronic cooling element / package integrated structure of the first embodiment and the hermetically sealed housing double structure of the second embodiment are combined. Therefore, in the third embodiment, the synergistic effect of each of the first and second embodiments can be obtained, and further improvement in cooling efficiency and prevention of LD deterioration can be expected.

It is needless to say that the present invention is not limited to the above-mentioned embodiments, and that various modifications may be made without departing from the scope of the present invention.

[0047]

As described above, according to the present invention, the optical cooling element / package integrated structure allows the optical cooling element to fully exhibit its cooling ability and efficiently cool the optical active element. A fiber module can be provided.

Further, the present invention provides an optical fiber module capable of completely hermetically sealing an optical active element even in a type in which an optical system holder is inserted into a package by a hermetically sealed housing double structure. You can

Furthermore, by combining the electronic cooling element / package integrated structure and the hermetically sealed housing double structure, it is possible to provide an optical fiber module capable of obtaining a stable optical output even in the long term.

[Brief description of drawings]

FIG. 1 is a sectional view showing a structure of a first embodiment of an optical fiber module according to the present invention.

FIG. 2 is a cross-sectional view showing an integrated structure of an electronic cooling element and a package of the same embodiment.

FIG. 3 is a sectional view showing a structure of a second embodiment of the optical fiber module according to the present invention.

FIG. 4 is a sectional view showing a first structural example of a conventional optical fiber module.

FIG. 5 is a sectional view showing a second structural example of a conventional optical fiber module.

FIG. 6 is a sectional view showing a third structural example of a conventional optical fiber module.

FIG. 7 is a cross-sectional view for explaining the cooling principle of the electronic cooling element of the conventional optical fiber module.

FIG. 8 is a sectional view showing the structure of the third embodiment of the optical fiber module according to the present invention.

[Explanation of symbols]

 1 LD 2 Heat Sink 3 LD Header 4 Support Plate 5 Temperature Detection Thermistor Resistor 7 Lens 8 Lens Holder 9,34 Cover 10 Optical Isolator 11 Optical Isolator Holder 12 Optical Fiber 13 Ferrule 14 Metal Sleeve 15, 31 Electronic Cooler 18 Optical System Holder 32 package 33 housing 162 opening window 311 heat absorption plate 312 heat dissipation plate 313 thermoelectric cooler 321, 331 window

Claims (3)

[Claims] 1. An optical fiber module in which an optical active element and an electronic cooling element are housed in a package, and an internal optical active element and an external optical fiber are optically coupled to each other. An optical fiber module characterized by being a part. 2. An optical system in which an optical active element and an electronic cooling element are housed in a package, an optical system holder is inserted in the package, and an internal optical active element and an external optical fiber are held by the optical system holder. In an optical fiber module optically coupled through a system, the optical active element is hermetically sealed inside the package with a small housing having a light transmission window on an optical axis plane. module. 3. An optical system in which an optical active element and an electronic cooling element are housed in a package, an optical system holder is inserted into the package, and an internal optical active element and an external optical fiber are held by the optical system holder. In an optical fiber module optically coupled via a system, an electronic cooling element / package integrated structure in which a heat dissipation plate of the electronic cooling element is a part of a package outer wall, and the photoactive element in an optical axis plane inside the package. An optical fiber module comprising a hermetically sealed dual structure for hermetically sealing in a small housing having a light transmission window.